La(NO3)3和Pr(NO3)3对高岭石脱羟基动力学的影响

采用热重和微商热重(TG/DTA)综合热分析技术在不同升温速率下研究了掺入La(NO₃)₃和Pr(NO₃)₃的高岭石的热分解过程, 利用Coats-Redfern积分法和Achar微分法对热分析实验数据进行动力学计算, 得到了高岭石脱羟基反应过程中的控制机理函数、 活化能和指前因子等动力学参数; 分析了2种稀土掺入对高岭石脱羟基过程动力学参数的影响, 并用Ozawa法对活化能进行了验证. 结果表明, 未掺稀土和掺入Pr(NO₃)₃的高岭石的脱羟基反应过程均受化学反应模型F₃控制, 反应的活化能分别为307.94和282.86 kJ/mol, 指前因子lnA的值分别为47.8980和44.1718; 掺入La(NO₃)₃的高岭石脱羟基反应过程控制机理函数发生改变, 受化学反应模型F₂控制, 反应活化能为196.02 kJ/mol, 指前因子lnA的值为29.5551. 与未掺稀土的高岭石对比, 掺入Pr(NO₃)₃后活化能和指前因子略有降低; 而掺入La(NO₃)₃后则显著降低, 分别降低了36.34%和38.30%. 采用Ozawa法验证得到的活化能与Coats-Redfern积分法和Achar微分法结果一致.     

硝酸碳酰肼合钴、镍、铜含能配合物结构和性质的理论研究

对硝酸三碳酰肼合钴([Co(CHZ)₃](NO₃)₂)、硝酸三碳酰肼合镍([Ni(CHZ)₃](NO₃)₂)和硝酸二碳酰肼合铜([Cu(CHZ)₂(NO₃)₂])进行密度泛函理论计算研究, 获得其稳定分子的几何构型、电子结构、红外光谱以及热化学性质. 研究结果表明, 这三种配合物均表现出六配位八面体结构, 而铜配合物中的硝酸根参与了配位. 自然键轨道分析表明, 配体和金属离子之间存在供体-受体相互作用, 致使配位氨基N—H键上的成键轨道电子发生离域, 进而导致氨基N—H键的电子占据数降低、键长增大、键级减小、伸缩振动频率红移, 这与实测红外光谱变化规律很好地吻合. 标题化合物的金属离子均为＋1氧化态, 金属-氮配位键都是共价键, 而Cu—O配位键是离子键. 通过计算求得理论反应热, 预测这些配合物的合成均为放热反应; 由生成热大小推测标题物的稳定性次序为[Ni(CHZ)₃](NO₃)₂＞[Co(CHZ)₃](NO₃)₂＞[Cu(CHZ)₂(NO₃)₂], 与实测热稳定性次序完全吻合.     

5-取代-3,4-二卤-2(5H)-呋喃酮的Sonogashira偶联反应

以5-取代-3,4-二卤-2(5H)-呋喃酮为底物进行Sonogashira偶联反应, 考察了反应温度、反应时间、钯催化剂种类与用量、碱种类与用量、溶剂、底物结构等对偶联反应的影响, 合成了28种新的2(5H)-呋喃酮衍生物, 其结构用IR, ¹H NMR, ¹³C NMR, MS和元素分析等方法进行了表征. 在优化的反应条件下, 即反应溶剂为甲苯、催化剂为3 mol% Pd(PPh₃)₄和10 mol% CuI、碱为6 equiv. KF、反应时间72 h、反应温度30 ℃时, 反应产率42%～84%. 利用该Sonogashira偶联反应合成新型的多官能团烯二炔结构化合物, 不仅合成途径简捷、反应条件温和, 绝大部分反应产率中等以上, 而且无需额外加入配体, 适用于芳香的和脂肪的末端炔烃.     

多苯并咪唑锰( Ⅱ )配合物的合成及对DNA凝聚的促进作用

以多苯并咪唑配体1,1,4,7,7-五(2-苯并咪唑甲基)-二乙基三胺(DTPB)为主配体, 合成了锰(Ⅱ)配合物[Mn(DTPB)Ac]Ac·8H₂O(1)和[Mn₂(DTPB)(NO₃)₂(H₂O)₂][Mn₂(DTPB)(NO₃)₂(H₂O)(CH₃OH)]·(NO₃)₄·5CH₃OH·H₂O(2), 并对其进行了表征. 利用紫外-可见吸收光谱和黏度实验研究了配合物1和2与DNA的相互作用, 发现这2个配合物均能与DNA结合, 并对配合物与DNA作用的机理进行了探讨. 利用琼脂糖凝胶电泳和直角光散射(RALS)技术研究了配合物1和2促进DNA凝聚的性质. 结果表明, 在近中性条件下2个配合物都能促使DNA凝聚. 利用透射电子显微镜(TEM)观察了不同凝聚体的形态.     

三氟甲磺酸铁催化新型1,3,5-三苯基苯类化合物的合成

以苯乙酮类化合物为原料,三氟甲磺酸铁［Fe(OTf)₃］为催化剂,经自身三聚缩合反应合成了18个1,3,5-三苯基苯类化合物(2a~2r),其中2o~2r为新化合物,其结构经¹H NMR, ¹³C NMR和HR-MS（ESI）表征。研究了催化剂种类及其用量、溶剂、温度和反应时间对2a产率的影响。结果表明：在最佳反应条件［Fe(OTf)₃ 0.02 eq.,甲苯为溶剂,于100 ℃反应4 h］下,2a产率91%。     

对苯二甲酸根桥联的双铜(Ⅱ)和双锰(Ⅱ)配合物的合成和长程磁交换作用

合成和表征了4种新型配合物[Cu₂(TPHA)(NO₂-Phen)₁](ClO₁)₂·H₂O、[Cu₂(TPHA)(Me-bpy)₁](ClO₁)₂、[Mn₂(TPHA)(NO₂-Phen)₁](ClO₁)₂·2H₂O和[Mn₂(TPHA)(Me-bpy)₁](ClO₁)₂(TPHA:对苯二甲酸根阴离子;NO₂-Phen:5-硝基-1,10-菲绕啉;Me-bpy:4,4'-二甲基-2,2'-联吡啶).测定了配合物的变温磁化率,并求出了交换积分J分别为-5.04、-6.52、-0.68及-0.73cm^-1.     

一例新型三重穿插锌(Ⅱ)配位聚合物的合成及热稳定性能

在水热条件下，以1,4-二咪唑丁烷（1,4-BIB）、对苯二甲酸（H₂TPA）和Zn(NO₃)₂·6H₂O为原料,合成了一例新型的配位聚合物[Zn(1,4-BIB)_0.5(TPA)]_n(CCDC: 983546),其结构和性能经IR,元素分析,XRD和TGA表征。结果表明：[Zn(1,4-BIB)_0.5(TPA)]_n具有三重穿插三维多孔骨架结构，热稳定性较好。     

低活化比制备天然气吸附剂： 活化助剂提高吸附剂性能

以石油焦为原料、KOH为主活化剂,在低活化比m_KOH∶m_C＝2∶1下制备吸附剂,考察了活化助剂KNO₃、NaNO₃、Mg(NO₃)₂、Ni(NO₃)₂和HJ对吸附剂储气性能的影响,对活化助剂提高吸附剂性能的机理进行了分析。结果表明,活化物料中加入适量助剂KNO₃、Mg(NO₃)₂、Ni(NO₃)₂或HJ能显著提高吸附剂性能,HJ与Mg(NO₃)₂、Ni(NO₃)₂协同活化的效果最好。其中,Mg(NO₃)₂、HJ加入量均为10 %（助剂与石油焦质量分数）下制备的吸附剂样品在25℃、3.5MPa下对甲烷质量吸附量达0.143,有效体积释放量达117.1,性能超过活化比m_KOH∶m_C=3∶1、无助剂下制备的吸附剂。     

新型苯并咪唑类配体配合物的合成及其性能

以苯并咪唑（HL¹）和3,6 二氯哒嗪在钠催化下反应制得配体3-氯-6-(苯并咪唑-1-基)哒嗪(L²）;采用溶液法和水热法,L¹分别与含有银、铜过渡金属盐反应合成了3种新的有机金属苯并咪唑配合物［AgL¹］_n(1),［Cu₄(HL¹)₄(O)(Cl)₆］(2)和{［Cu(HL¹)₂］·SiF₆}(3);采用溶液法,L²与Zn(NO₃)₂·6H₂O经配位反应合成了配合物{［Zn(L²)₃(NO₃)］NO₃}(4),其结构经IR,元素分析和X-射线单晶衍射表征。结果表明：1通过苯并咪唑桥连形成一维链状结构,2由苯并咪唑和氯离子桥接形成四核结构,3和4均显示一个单核结构,3的金属中心原子采用二配位构型,4的金属中心原子采用四配位构型。此外,研究了配体HL¹与1,及配体L²与4的荧光性能。结果表明：与HL¹相比,1的最大发射波长发生了红移;而4相对于配体L²其最大发射峰发生明显蓝移。     

沉淀方式对微波辐射老化制备CuO/ZnO/Al2O3催化剂性能的影响

采用微波辐射老化沉淀母液的方法,着重考察了沉淀方式对制备的CuO/ZnO/Al₂O₃催化剂及其前驱体的结构和催化性能的影响。实验结果表明,沉淀方式对催化剂的活性和稳定性影响较大,其活性顺序为分步沉淀法二＞并流共沉淀法＞分步沉淀法一＞反加法＞正加法。通过XRD、DTG、H₂-TPR等表征分析表明,先并流沉淀Al(NO₃)₃溶液和Na₂CO₃溶液,再并流沉淀Cu(NO₃)₂-Zn(NO₃)₂混合溶液与剩下的Na₂CO₃溶液,然后微波辐射老化所制备前驱体中含有更多的绿铜锌矿 (Cu,Zn)₅ (CO₃)₂(OH)₆物相,焙烧后形成的CuO-ZnO协同作用强,且CuO分散性好,H₂还原温度较低,催化活性和稳定性也较高。     

Mechanisms of the oxidations of NAD(P)H model Hantzsch 1,4-dihydropyridines by nitric oxide and its donor N-methyl-N-nitrosotoluene-p-sulfonamide

4-Substituted derivatives of Hantzsch 1,4-dihydropyridine were treated by nitric oxide (NO) or its donor N-methyl-N-nitrosotoluene-p-sulfonamide (MNTS) to give the corresponding pyridine derivatives. When the 4-substituted group was methyl, ethyl, n-propyl, and aryl groups, it was preserved, but when the group was isopropyl or benzyl one, it was lost. 2,3-Dichloro-5, 6-dicyano-1,4-benzoquinone (DDQ) was used in place of NO and MNTS to react with the 4-substituted Hantzsch 1,4-dihydropyridines, no the corresponding 4-dealkyl Hantzsch pyridines were obtained from all the reactions. 1-Benzyl-1,4-dihydronicotinamide (BNAH), a close analogue of Hantzsch 1,4-dihydropyridine (HEH), was used instead of HEH to react with either of NO and MNTS, no reactions were observed for 3 days. Replacement of HEH by N-d-HEH and HEH-4,4-d(2) to react with NO, MNTS and DDQ gave the observed kinetic isotope effects of 3.1 and 1.4 for NO, 1.1 and 1.3 for MNTS, and 1.1 and 2.1 for DDQ, respectively. When p-dinitrobenzene, an electron-transfer inhibitor, was added into the title reaction systems, no remarkable inhibitory effect was observed. These results indicated that the oxidation of HEH by NO was initiated by hydrogen transfer from the N(1)-position to give the corresponding aminyl radical, which then underwent homolytic cleavage to become the final aromatized product (A). But the reaction of HEH with MNTS was initiated by nitrosation to give the corresponding N-nitroso compound, which was subsequently subjected to two steps of homolytic cleavage to afford the aromatized Hantzsch pyridine A.     

2-硝基-2-亚硝基丙烷氧化1,4-二氢Hantzsch酯衍生物的反应机理

4位取代的Hantzsch酯(HEH)衍生物在2-硝基-2-亚硝基丙烷的氧化下生成相应的吡啶类化合物. 将N-氘代1,4-二氢Hantzsch酯(N-d-HEH)和4,4'-双氘代1,4-二氢Hantzsch酯(4,4'-2d-HEH)分别代替HEH与2-硝基-2-亚硝基丙烷反应, 得到的同位素效应常数分别为1.03(k_N-H/k_N-D)和1.78(k_C4-H/k_C4-D), 表明1,4-二氢Hantzsch酯中4位上氢原子所涉及的C4-H键的断裂发生在反应的决速步骤中或在决速步骤之前, 而1位上氢原子所涉及键的断裂则不在决速步骤中. 由4位取代的HEH酯衍生物的氧化电位与2-硝基-2-亚硝基丙烷的还原电位可在热力学上判断该反应不是由电子转移引发的. 向反应体系中加入单电子转移抑制剂对二硝基苯, 反应未受到明显抑制, 进一步证明了上述推断. 据此推测, 反应可能是通过NO⁺直接对HEH酯上氮原子的亲电历程引发的.     

Hantzsch synthesis of 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(o-methoxyphenyl)-1,4-dihydropyridine; a novel cyclisation leading to an unusual formation of 1-amino-2-methoxy-carbonyl-3,5-bis(o-methoxyphenyl)-4-oxa-cyclohexan-1-ene

Hantzsch condensation of two equivalents of methyl-3-aminocrotonate with (m- and p)-methoxybenzaldehyde afforded the expected products 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(m-methoxyphenyl)-1,4-dihydropyridine and 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(p-methoxyphenyl)-1,4-dihydropyridine, whereas o-methoxy-benzaldehyde produced mainly 1-amino-2-methoxycarbonyl-3,5-bis(o-methoxy-phenyl)-4-oxa-cyclohexan-1-ene. The structure of the product, not previously reported in the literature, was determined by 1D and 2D NMR spectra and its MS fragmentation. This is the first example of cyclisation leading to a substituted pyran rather than 1,4-DHP under typical Hantzsch reaction conditions. A plausible mechanism for its formation is postulated.     

(NH4)2.5H0.5PW12O40-catalyzed rapid and efficient one-pot synthesis of dihydropyridines via the Hantzsch reaction under solvent-free conditions

A heterogeneous reaction with the ammonium salt of 12-tungstophosphoric acid as catalyst has been designed for synthesis of 1,4-dihydropyridine and polyhydroquinoline via the Hantzsch condensation. Molten tetrabutylammonium bromide ionic liquid was used as reaction medium.     

One-step, synthesis of Hantzsch esters and polyhydroquinoline derivatives in fluoro alcohols

Hantzsch 1,4-dihydropyridine, polyhydroquinoline and 1,8-dioxodecahydroacridines derivatives were synthesized in excellent yields in trifluoroethanol (TFE). The solvent (TFE) can be readily separated from reaction products and recovered in excellent purity for direct reuse.     

Rapid and efficient aromatization of Hantzsch 1,4-dihydropyridines with Potassium peroxomonosulfate catalyzed by manganese(III) Schiff base complexes

Rapid and efficient oxidation of Hantzsch 1,4-dihydropyridine with Potassium peroxomonosulfate is reported. The Mn(III)-salophen/monopersulfate catalytic system converts 1,4-dihydropyridines to their corresponding pyridine derivatives at room temperature in a 1:1, CH₃CN/H₂O mixture. The ability of various Schiff base complexes in the oxidation of 1,4-dihydropyridine was also investigated.     

Silica-supported perchloric acid (HClO4–SiO2): a mild, reusable and highly efficient heterogeneous catalyst for multicomponent synthesis of 1,4-dihydropyridines via unsymmetrical Hantzsch reaction

Facile synthesis of some 1,4-dihydropyridine derivatives via Hantzsch reaction of 5,5-dimethyl-1,3-cyclohexanedione (dimedone), 1,3-diphenyl-2-propen-1-one derivatives and ammonium acetate under solvent-free condition in the presence of silica-supported perchloric acid (HClO₄–SiO₂) is described. The catalyst is easily prepared, stable, reusable and efficient under the reaction conditions.     

Studies on nilvadipine. I. Synthesis and structure-activity relationships of 1,4-dihydropyridines containing novel substituents at the 2-position.

The synthesis of new 1,4-dihydropyridine derivatives containing novel substituent at the 2-position of the nucleus via the key intermediate 2-formyl-1,4-dihydropyridines (X), is described. The aldehydes (X) were prepared by hydrolysis of the acetals (IX) which were obtained from aryl aldehyde (V) and alkyl 4,4-dialkoxyacetoacetate (VI) by the Knoevenagel reaction and treatment with alkyl 3-aminocrotonate (VIII) according to the modified Hantzsch method. The formyl group of the aldehydes (X) was reactive enough to be converted to a variety of functional groups such as hydroxymethyl, cyano, substituted iminomethyl, carbamoyl, semicarbazone, substituted vinyl, ethynyl, and so on. In all of the novel compounds we prepared, 2-hydroxymethyl- and 2-cyano-1,4-dihydropyridines (IV and XXII) were found to possess potent activities in preliminary biological evaluations on hypotension in normotensive rats and on an increase in coronary blood flow in pentobarbital-anesthetized dogs. Optimization research in order to obtain a more potent compound was accomplished in the 2-hydroxymethyl- and 2-cyano-1,4-dihydropyridine series. We selected isopropyl 2-cyano-3-methoxycarbonyl-4-(3-nitrophenyl)-6-methyl-1,4-dihydropyridine -5-carboxylate (XXIIj) as a candidate compound for further biological evaluation studies. Fortunately, XXIIj (nilvadipine) has been accepted in clinical use for the treatment of hypertension.     

Use of pyridinium ionic liquids as catalysts for the synthesis of 3,5-bis(dodecyloxycarbonyl)-1,4-dihydropyridine derivative

The synthesis of cationic amphiphilic 1,4-dihydropyridine derivative, potential gene delivery agent is achieved via an efficient multi-step sequence. The key step of this approach is a two-component Hantzsch type cyclisation of 3-oxo-2-[1-phenylmethylidene]-butyric acid dodecyl ester and 3-amino-but-2-enoic acid dodecyl ester utilising bis(2-hydroxyethyl)ether as a solvent and 1-butyl-4-methylpyridinium chloride as a catalyst. The 1,4-dihydropyridine derivative with long alkyl ester chains at positions 3 and 5 of the 1,4-DHP ring — 3,5-bis(dodecyloxycarbonyl)-2,6-dimethyl-4-phenyl-1,4-dihydropyridine was obtained in substantially higher yield with respect to classical Hantzsch synthesis. Bromination of this compound followed by nucleophilic substitution of bromine with pyridine gave the desired cationic amphiphilic 1,4-dihydropyridine.      

A microwave-assisted bismuth nitrate-catalyzed unique route toward 1,4-dihydropyridines

The classical Hantzsch reaction is one of the simplest and most economical methods for the synthesis of biologically important and pharmacologically useful 1,4-dihydropyridine derivatives. Bismuth nitrate pentahydrate under microwave irradiation is proven to act as a very efficient catalyst for a one-pot, three-component synthesis of 1,4-dihydropyridines in excellent yields from diverse amines/ammonium acetate, aldehydes and 1,3-dicarbonyl compounds within 1-3 min under solvent-free conditions. The present environmentally benign procedure for the synthesis of 1,4-dihydropyridines is suitable for library synthesis and it will find application in the synthesis of potent biologically active molecules. The excellent yield and extreme rapidity of the method is due to a concurrent effect of the catalyst and microwave irradiation.